TR6 '72 Engine Project, Some Day

[Martin Secrest]

My '72 has almost 90K on the odometer, and while the engine runs fine and doesn't really drink (oil) or smoke, I'm pondering an engine rebuild in the next year or two. Not a project I *want* to do, but I would be happy to get it done and drive the car until the end of time. The rest of the car is very sold and completely sorted, so the engine is kind of the last shoe to drop. If I do the rebuild, I'll be adding some reasonable amount of horsepower, with head work and a cam swap. Probably will stick with the twin Strombergs, but who knows.

So my question is ... what are lessons people have learned in the past for this? Pitfalls to avoid? Things to do right the first time, etc. And though I have never seen anyone do it, or even talk about it, is it possible to rebuild the engine in situ? I mean, I have to ask.

 

[poolboy]

It depends. If you need to have the cylinders bored for larger pistons rather than just crosshatched honed for fresh rings and the same size pistons an/or if you need to thave the crankshaft turned for oversize bearings, you will need the engine out.
The only tip I have at the moment is to use Hastings piston rings, even if you have to buy them separate from what brand may come with new pistons

 

[glemon]

My engine was rebuilt at 90,000 ish miles (though I had no documentation of actual miles or previous work). A few disjointed notes. It didn't need a rebuild. We replaced bearings and piston rings with standard size, wear was not bad at all.

If you decide not to rebuild do check the crankshaft end float, lots of information out there on the internet.

I went a similar route to you on performance. Shaved the head, sports exhaust, mild cam, lightened flywheel, made a noticeable difference in performance with no sacrifice in driveability. If you are having head work done shaving the head is probably the best bang for the buck modification. Ups HP and Torque across the board, no drivability trade-off.

 

[Bob Claffie]

My standard answer. If it ain't broke, don't fix it".

 

[Martin Secrest]

Interesting responses. Actually about 10K miles ago I freshened the bottom end bearings, all of them, though I'm not 100% sure I did the best job. I was concerned about the idea of just pulling the head and porting and shaving it, what the extra stress of that increased HP might do to the engine as a whole. But maybe nothing?

 

[poolboy]

A freshened head, shaved to increase compression, valves and seats recut, seated and sealing tight might contribute to increased blowby and oil consumption past rings with 90k miles on them....I say 'might' but I bet you'd notice it.

 

[Martin Secrest]

I think you're right.